tzdata rule group

Detroit

Historical rule context · 1 represented zone

A rule group describes recurring clock changes. It is not itself a place or an IANA time-zone identifier.

First rule
1948
Last rule
1948
Rule entries
2
Source files
northamerica

Notes from the time database

Context for this rule

These source notes are preserved from tzdata. They help explain a rule’s period, without adding claims beyond the source.

1946–1975

Rule context

Michigan Michigan didn't observe DST from 1968 to 1973. The tzdata source notes that Michigan started using standard time on 1885-09-18, but Howse writes (pp 124-125, referring to Popular Astronomy, 1901-01) that Detroit kept local time until 1900 when the City Council decreed that clocks should be put back twenty-eight minutes to Central Standard Time. Half the city obeyed, half refused. After considerable debate, the decision was rescinded and the city reverted to Sun time. A derisive offer to erect a sundial in front of the city hall was referred to the Committee on Sewers. Then, in 1905, Central time was adopted by city vote. This story is too entertaining to be false, so go with Howse over Shanks. Garland (1927) writes "Cleveland and Detroit advanced their clocks one hour in 1914." This change is not in Shanks. We have no more info, so omit this for now. Due to a complicated set of legal maneuvers, in 1967 Michigan did not start daylight saving time when the rest of the US did. Instead, it began DST on Jun 14 at 00:01. This was big news: the Detroit Free Press reported it at the top of Page 1 on 1967-06-14, in an article "State Adjusting to Switch to Fast Time" by Gary Blonston, above an article about Thurgood Marshall's confirmation to the US Supreme Court. Although Shanks says Detroit observed DST until 1967-10-29 00:01, that time of day seems to be incorrect, as the Free Press later said DST ended in Michigan at the same time as the rest of the US. Also, although Shanks reports no DST in Detroit in 1968, it did observe DST that year; in the November 1968 election Michigan voters narrowly repealed DST, effective 1969. Most of Michigan observed DST from 1973 on, but was a bit late in 1975.

Original rule fields

Recorded rule entries

Structured directly from tzdata’s Rule lines.

FromToTypeInOnAtSave
1948only-AprlastSun2:001:00
1948only-SeplastSun2:000